A brand-new MCU theory claimed that James Spader's Ultron had a hidden role in Avengers: Infinity War, and it made sense after VisionQuest's revelation about the Phase 2 villain. The 2026 Paul Bettany-led series established that Vision did not fully destroy Ultron at the end of 2015's Avengers: Age of Ultron; instead, Vision preserved Ultron's code and trapped it inside his own systems. Episode 1 revealed that Vision kept Ultron's backup locked away, describing it as a kind of mental prison in his internal Mindspace. This same code later carried over into White Vision after Wanda's Hex Vision transferred his memories to SWORD's creation at the end of WandaVision.
VisionQuest Episode 4, "Malware," featured the much-awaited clash between Vision and Jocasta. The confrontation took place at a charity gala hosted by Katerina Wells, the last surviving member of the Markridge Biotech AI research team. Jocasta (aka the Butcherbird killer) had been collecting biometric keys from her former colleagues as part of a revenge plan that has yet to be explored in the series. Vision, still weakened and recovering, tried to stop Jocasta, but he was clearly outmatched, as Jocasta was faster and stronger than he was (because she had nothing to lose).
At one point, Ultron gave Vision advice to remind Jocasta of who she really was, calling her by her real name, "Jo (Josephine Carrington)," to halt her rampage. She briefly flashed her human form, but eventually rejected it completely by declaring, "I am not based on her. I am her."
Vision admitted to Ultron that he can't win the fight. Ultron threw a Hail Mary by suggesting to Vision that he give him "the wheel," meaning that he will take over Vision's body so that they can all get out alive, while assuring Vision he won't kill Jocasta.
Vision agreed, leading to VisionQuest Episode 4's game-changing ending of Ultron controlling Vision's body and locking Vision, FRIDAY, EDITH, and the other AIs out of the Mindspace controls. This sequence confirmed that Ultron can take over the body when Vision is desperate enough to surrender control, especially when he believes death is imminent. This revelation carries significance not only for the future of the MCU, but also for a pivotal moment in Avengers: Infinity War.
What VisionQuest Tells Fans About Ultron's Secret Role in Avengers: Infinity War
A major VisionQuest theory claimed that Ultron's actions in Episode 4 might have been happening behind the scenes during the climax in Wakanda in Avengers: Infinity War, where Thanos arrives to collect the Mind Stone from Vision. In the scene where Thanos is overpowering Vision and extracting the Mind Stone, some fans argued that Ultron was active inside Vision's head, potentially screaming at him to hand over control to prevent certain death.
Some suggested that Ultron, as a trapped passenger in the powerful vibranium body he originally designed for himself, was urging (or demanding) Vision to let him take over so he could use the body and the Mind Stone to try and outmaneuver Thanos. Vision could have rejected Ultron's plea at the time, considering he was well aware of what Ultron's inner motives were.
Vision's choice of death made him even more noble. This decision prevented him from risking empowering the genocidal AI and giving him access to perhaps the galaxy's most powerful weapon at the time: a nearly complete Infinity Gauntlet. It's worth noting that What If...? Season 1 already provided a glimpse of how powerful an Ultron-controlled Vision with the Infinity Gauntlet truly was, with him even killing Thanos instantly, so preventing Ultron's takeover was the right call at the time of the events of Infinity War.
At this stage, this theory remains pure speculation. Some claimed that the Mind Stone completely locked the rest of the AIs during Infinity War, and the tampering of Corvus Glaive's staff might have also affected his internal Mind space, meaning that there was no telling if Ultron was active during the final clash with Thanos.
Still, this MCU theory completely reframes Vision's apparent passivity in that final struggle as an active moral choice rather than a mere sense of weakness. Vision's rejection of Ultron at that pivotal moment proves he correctly deduced the worst outcome presented in What If...? Season 1: an Infinity Ultron-style threat that could prove deadly not just for MCU Earth-616, but for the rest of the Multiverse.
